Markham man charged in Tinley Park shooting

Photo from Tinley Park police

Booking photo of Christopher Dyson

Booking photo of Christopher Dyson (Photo from Tinley Park police)

Naomi NixTribune reporter

A fatal shooting outside a Tinley Park convenience store last week stemmed from a Craigslist website transaction to swap electronics goods that turned into an argument when the victim and assailant met to close the deal, Cook County prosecutors said Saturday.

Christopher Dyson, 18, was charged with first-degree murder and armed robbery after he and Thomas Mastro, 24, allegedly fought over an online gaming system outside a 7-Eleven convenience store, prosecutors and police said.

Dyson, of 16631 Winchester Avenue in Markham, allegedly agreed to trade his iPhone for Mastro’s PlayStation gaming system after Mastro placed an ad on Craigslist, said Assistant State's Attorney Dan Calandriello.

The two met at the 7-Eleven in Tinley Park on Thursday around 3 p.m. to make the exchange, Calandriello said.

A video obtained by police shows Dyson placing a box inside a Mercedes Benz, according to Calandriello.

Mastro, of the 6900 block of Coachwood Trail in Tinley Park, retrieved the box and the two began to struggle over it before Dyson pulled out a gun and shot Mastro in the chest, Calandriello alleged.

Dyson put the box in his car and sped out of the parking lot and headed north on Oak Park Avenue.

A witness flagged down an off-duty Tinley Park police officer nearby, who started chasing after Dyson, sometimes at speeds faster than 90 mph, according to Calandriello.

Dyson abandoned his car in the parking lot of an Oak Forest restaurant and fled into a nearby forest preserve, Calandriello said. He was arrested after a 45-minute manhunt, police said.